Extreme Agility Micro Aerial Vehicle - Control of Hovering Maneuvers for a Mini-Aerial Vehicle with an Onboard Autopilot System

Abstract : Mini Aerial Vehicles (MiniAV) are involved in various unmanned missions for both civil and military applications. These airplanes benefit from high maneuverability and can generally execute hovering and other acrobatic maneuvers. The small size of these vehicles, combined with their high maneuverability, have inspired numerous research studies in which these vehicles are envisioned for use in missions involving hazardous locations or situations in which human lives are at risk. The theoretical basis for measuring the attitude and altitude, and stabilizing a mini-aerial vehicle while being flown in a hovering position is presented. A cascaded PI control architecture based on quaternion attitude measurements and a PID altitude/throttle controller with anticipation due to aileron perturbations were formulated and implemented on an onboard autopilot. The implementation of the controllers on the onboard autopilot reduced previous system delays from 0.17s to 0.05s. The result was a significant increase in the amplitude margin from roughly 6 to 17dB in the pitch and yaw axes. The experimental data showed that throttle commands, compensated for aileron effects through an anticipation function, reduced the altitude hold error from +/- 25cm to +/- 10cm, thereby validating the necessity of a roll-throttle decoupler to stably hover an aircraft of this type at a fixed altitude.